The present invention relates to the improvement of trigger pull characteristics and mechanical safety of certain striker fired pistols which incorporate a pivoting sear to hold back the striker, and which is actuated by a trigger bar.
Certain striker-fired pistols such as the SIG SAUER® P320 incorporate a pivoting sear in the frame or receiver. This sear is spring loaded to interpose the sear face before the striker, thus holding it back in a cocked position against the substantial tension of the striker spring and positive engagement angles, unless and until the sear is rotated to free the striker and permit it to travel forward as it normally would to fire a primed cartridge.
The sear must present adequate engagement to the striker, and be sufficiently sprung, as to provide an objective measure of mechanical resistance to releasing the striker if the pistol is dropped or jarred. Certain pistol designs are dependent upon positively angled sear engagement surfaces and substantial sear spring tension to hold the striker and sear in engagement with an acceptable margin of mechanical safety.
During the normal sequence of operation, actuation of the sear to discharge the pistol is effected by the action of a trigger bar which transmits pressure and movement of the trigger to a leverage point on the sear. Pressure applied to the trigger must overcome the resistance of the sear engagement and springs to rotate the sear, defeat the striker safety lock mechanism, release the striker, and thus discharge the pistol. That sear engagement and springing have a direct effect upon both measurable and subjective trigger pull weight and feel, and therefore certain service pistols like the P320 are designed with relatively heavy trigger pulls measuring well above 6 pounds.
Competitive marksmen and other discerning or elite pistol users often prefer lighter trigger pulls with less perceived movement of the sear engagement and a more cleanly defined sear release feel as a demonstrable aid to precision marksmanship. Conventional methods of achieving a more preferable trigger pull typically involve reduced sear engagements, altered sear angles and reduced sear and striker springs to thus reduce both measurable and perceived trigger pull weight, and enhance subjective feel. Such methods typically compromise the original design's margin of mechanical safety against accidental mishandling or extreme use, if not eliminating that margin altogether. More sophisticated methods for achieving improved trigger qualities are typically not cross and reverse compatible within the applicable model line and involve custom tuning, limiting the practical utility of same as drop-in kits or for mass production as a factory-installed system.
This invention comprises a set of fire control components which may be configured to reduce trigger pull weight, enhance the subjective feel of the trigger pull, and improve the shooting qualities of the applicable pistol, while providing simple mechanisms to improve the system's mechanical reliability and safety values related to resistance to unintentional discharge from being dropped, jarred or otherwise mishandled.